CHTs - What is acceptable?

I haven't leaned much so far. Only the past 5 hours have I leaned any and
not agressively at that. I will run that one cylinder at 380-390 leaned at 75%. \
65% doesn't help but maybe 10 degrees. This is the hot cylinder. The
others run from 320 - 355. Number 3 is this hot one and number 5 is next but
20-30 degrees less. I feel as long as I keep it under 400 degrees except on
take off it should be ok. I drop back to 23 squared for extended climb and
use a more shallow climb for better cooling.


Trip



In article , says...


"TripFarmer" wrote:
I've got about 15 hours on 6 new Superior Millinieums and just
put in my first quart of oil since 2TT. I have a range of temps
at cruise from 320 - 380. They dropped a lot after about the
first 30 - 60 minutes of break in and seem to have stabilized
since to these numbers. The hot one will run 400-410 in a
full power climb in my PA28 235.

I have the same cylinders in a LYC O-360; they have 500+ hours on them. In
order to keep mine below 380 deg., I have to keep the cowl flaps wide open
in cruise in summer at 75% power. I can lean the engine in climb for better
performance, but it takes careful attention to the mixture to keep the CHTs
under 400.
--
Dan
C-172RG at BFM

"TripFarmer" wrote in message
...
What is an acceptable CHT in cruise? How hot can one stay in extended
cruise
flight? I've got 6 new ones and want to take care of them.


Thanks in advance.


Trip


Our club's Skylane has one CHT gauge with a big 'ol green range & no temps
on it. Any recommendations on how to use this rather "useless" gauge?

I feel as long as I keep it under 400 degrees except on
take off it should be ok. I drop

Can a cylinder heat up that much on takeoff? I have never looked.

Steven Barnes wrote:
Our club's Skylane has one CHT gauge with a big 'ol green range & no temps
on it. Any recommendations on how to use this rather "useless" gauge?

You don't, it is for reference only.
Lean until the engine starts to run rough, then enrich half- to one-turn
so it runs smooth again.

In article ,
(WARREN1157) wrote:

I feel as long as I keep it under 400 degrees except on
take off it should be ok. I drop

Can a cylinder heat up that much on takeoff? I have never looked.

yes. My 140 gets pretty close to 500 degrees during climbout
(500 is redline for my engine).

--
Bob Noel
Seen on Kerry's campaign airplane: "the real deal"
oh yeah baby.

Dave Butler wrote:

I agree the temperature a cylinder can tolerate probably doesn't depend on the
airframe, but the method of measurement might. Where is the CHT probe on the
cylinder? Don't know, but maybe Piper puts the probe in one hole, and Cessna in
another.

In a sense, you're probably right. There's a threaded hole in the cylinder head. The
probe goes there, no matter what the airframe. The only way the airframe could make a
difference is if a) they have the probe in only one cylinder and b) the
temperatures on the other cylinders are known to be significantly different.

So, if Piper puts the probe in cylinder #1 for one aircraft and cylinder #4 in
another, the allowable max temperatures are likely to be different for the two.

George Patterson
If you want to know God's opinion of money, just look at the people
he gives it to.

Steven Barnes wrote:

Our club's Skylane has one CHT gauge with a big 'ol green range & no temps
on it. Any recommendations on how to use this rather "useless" gauge?

That's what my Maule has. I just keep it in the green during climb and descent and
check it every once in a while during cruise.

George Patterson
If you want to know God's opinion of money, just look at the people
he gives it to.

"TripFarmer" wrote in message
...
I just don't buy that "airframe" stuff. A cylinder head can only take
so much temperature for so long before it gives in. 400 degrees is
400 degrees no matter what airframe it's in. If I'm wrong please tell
me why.........

I've got about 15 hours on 6 new Superior Millinieums and just put in my
first quart of oil since 2TT. I have a range of temps at cruise from
320 - 380. They dropped a lot after about the first 30 - 60 minutes of
break in and seem to have stabilized since to these numbers. The hot one
will run 400-410 in a full power climb in my PA28 235.



I take it you have a good engine analyzer like the JPI 700?

Can a cylinder heat up that much on takeoff? I have never looked.

yes. My 140 gets pretty close to 500 degrees during climbout
(500 is redline for my engine).

Are takeoff and climbout the same thing?

on it. Any recommendations on how to use this rather "useless" gauge?

I had a 182 with the same. I would just use it for a quick reference. Lean it
until it was at the same place as before. For extended cruise I would re-lean
the engine by roughing the engine then smoothing it out.